Jimfs
An in-memory file system for Java 8+
...Developed by Google, it allows developers to create and manipulate file systems entirely in memory, making it ideal for testing, simulation, and temporary file operations without touching the actual disk. Jimfs supports most standard file operations, including file and directory creation, deletion, copying, symbolic and hard links, as well as stream-based file reading and writing. It also provides robust support for features like SecureDirectoryStream, WatchService for directory change notifications, and multiple attribute views (basic, posix, unix, dos, and acl). ...